Question 1

Which of the following best explains why Mendel chose pea plants for his experiments on heredity?

Accepted Answer

Pea plants have many true-breeding varieties and allow controlled mating, making them ideal for genetic studies.

Question 2

In Mendel's monohybrid cross between true-breeding purple-flowered and white-flowered pea plants, all F1 offspring had purple flowers. Which hypothesis does this result support?

Accepted Answer

The particulate hypothesis

Question 3

What is the difference between phenotype and genotype?

Accepted Answer

Phenotype refers to the physical appearance, while genotype refers to the genetic makeup.

Question 4

According to Mendel's law of segregation, what happens to alleles during gamete formation?

Accepted Answer

The two alleles separate so that each gamete receives only one allele.

Question 5

A plant with genotype Pp is crossed with a plant with genotype pp. What is the expected phenotypic ratio of the offspring if P is dominant for purple flowers and p is recessive for white flowers?

Accepted Answer

$$1:1 ($$purple:white)

Question 6

In a dihybrid cross between two heterozygous pea plants (YyRr x YyRr), what is the probability of obtaining an offspring with the genotype yyrr?

Accepted Answer

$$\frac{1}{16}$$

Question 7

Which of the following best describes Mendel’s law of independent assortment?

Accepted Answer

Each pair of alleles segregates independently of other pairs during gamete formation.

Question 8

A testcross is performed between a pea plant with purple flowers of unknown genotype and a white-flowered plant (pp). If some offspring have white flowers, what is the genotype of the purple-flowered parent?

Accepted Answer

Pp

Question 9

Which of the following is an example of incomplete dominance?

Accepted Answer

A cross between red and white snapdragons produces pink offspring.

Question 10

In human blood types, the IA and IB alleles are both expressed in individuals with genotype IAIB. This is an example of:

Accepted Answer

Codominance

Question 11

A Labrador retriever’s coat color is determined by two genes: one for pigment color (B = black, b = brown) and one for pigment deposition (E = pigment deposited, e = no pigment deposited). What is the phenotype of a dog with genotype bbEE?

Accepted Answer

Brown

Question 12

Which inheritance pattern is most likely responsible for the continuous variation in human skin color, as shown by a bell-shaped curve in the population?

Accepted Answer

Polygenic inheritance

Question 13

If a plant with genotype AaBb is self-crossed, what is the probability that an offspring will be homozygous recessive for both genes (aabb)?

Accepted Answer

$$\frac{1}{16}$$

Question 14

Which of the following statements about dominant and recessive alleles is correct?

Accepted Answer

A dominant allele determines the phenotype in a heterozygote.

Question 15

A woman is a carrier for cystic fibrosis (genotype Cc, where c is the recessive disease allele) and her partner is also a carrier. What is the probability that their child will have cystic fibrosis?

Accepted Answer

$$\frac{1}{4}$$

Question 16

Which of the following best describes epistasis?

Accepted Answer

One gene affects the phenotypic expression of another gene.

Question 17

If a gene has three alleles in a population (A, B, and C), how many possible genotypes can exist for this gene?

Accepted Answer

6 (AA, AB, AC, BB, BC, CC)

Question 18

In a trihybrid cross (AaBbCc x AaBbCc), what is the probability of obtaining an offspring with genotype aabbcc?

Accepted Answer

$$\frac{1}{64}$$

Question 19

Which of the following is a real-world example of codominance in humans?

Accepted Answer

ABO blood group system

Question 20

A couple, both with genotype IAi for blood type, have a child. What is the probability that their child will have blood type O?

Accepted Answer

$$\frac{1}{4}$$

Lecture 17 (Unit 2) -Mendel and the Gene Idea: Principles of Heredity and Patterns of Inheritance

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Study guide - Flashcard